I think his background story will appear sooner or later, but i'm guessing something around the lines of he was also a substitute Shinigami like Ichigo. Perhaps they gave him the chance to be a captain but something went wrong? I don't know - but Shinigami are 'dead' (or atleast not part of the living world), right? So I doubt he could've simply been a captain. It wouldn't make sense.

but if he only had a chance to be a captain then why does he have a captains robe while in shinigami form

Well thats a good question, perhaps he was given them but never offically became a Captain? He couldn't be a captain unless he's 'dead'. It's the same reason why Ichigo is a Substitute Shinigami and not a full Shinigami I believe.

Even if he was a captain, I -highly- doubt it's as simple as 'he was a captain 50 years ago bla bla'.

Well thats a good question, perhaps he was given them but never offically became a Captain? He couldn't be a captain unless he's 'dead'. It's the same reason why Ichigo is a Substitute Shinigami and not a full Shinigami I believe.

Even if he was a captain, I -highly- doubt it's as simple as 'he was a captain 50 years ago bla bla'.

I definitely think that you're right, in that I seriously doubt that Isshin is 'just' anything, I'm guessing his story is going to be complex. That said, he still could be a 'real' shinigami, in that Urahara and the vizoreds were all real shinigami who are now living on earth in human disguise, in flesh bodies. There's no reason why the gigai aren't 'full function.'

Well thats a good question, perhaps he was given them but never offically became a Captain? He couldn't be a captain unless he's 'dead'. It's the same reason why Ichigo is a Substitute Shinigami and not a full Shinigami I believe.

Even if he was a captain, I -highly- doubt it's as simple as 'he was a captain 50 years ago bla bla'.

I definitely think that you're right, in that I seriously doubt that Isshin is 'just' anything, I'm guessing his story is going to be complex. That said, he still could be a 'real' shinigami, in that Urahara and the vizoreds were all real shinigami who are now living on earth in human disguise, in flesh bodies. There's no reason why the gigai aren't 'full function.'

Actually you bring up a very good arguement there, it's entirely possible Isshin could just be in a gigai and died a while ago. Maybe he was a substitute shinigami before he died - and when he did die, he became a captain for a while before perhaps having to look after his children? I doubt he could've became a captain in 10 years or so, seeing as I doubt gigai have.. that function. xD

Isshin was definitely a soul reaper who possesses captain level soul reaper ability when he fought Aizen. Plus we know he used the final getsuga tensho which means he loss his soul reaper powers,but obviously the lost of your spiritual pressure is not finite. Personally I think maybe he left the soul society because he fell in love with Ichigo's mother and I don't think soul reapers and humans can be married. Isshin was more than likely a very powerful captain probably of squad 10 or captain of the kido corps possibly but that highly unlikely. What is know he is far more than a former ordinary soul reaper.

Isshin was definitely a soul reaper who possesses captain level soul reaper ability when he fought Aizen. Plus we know he used the final getsuga tensho which means he loss his soul reaper powers,but obviously the lost of your spiritual pressure is not finite. Personally I think maybe he left the soul society because he fell in love with Ichigo's mother and I don't think soul reapers and humans can be married. Isshin was more than likely a very powerful captain probably of squad 10 or captain of the kido corps possibly but that highly unlikely. What is know he is far more than a former ordinary soul reaper.

Don't read this unless you've read the most recent manga.

Spoiler Alert! Click to show or hide

I think it's all coming together now. Isshin used to be a captain. He was a captain during the time the Quincies were being exterminated. It's possible that a bit before the extermination campaign, Isshin was on a mission and met Masaki.

When the orders were given that the extermination would take place, he made plans to escape with Masaki to the human world. I'm thinking that the head captain or someone of high power found out about these plans and tried to kill Masaki and him. At this point he could have used Final Getsuga Tenshou, effectively making him lose his powers indefinitely.

I think the above is more plausible since during the Pendulum arc, we see no signs of Isshin, so he probably escaped to the Human World before the whole Hollowfication experiments took place. (causing Urahara and Yoruichi to escape using Gigai)

Once Urahara and Yoruichi escaped to the human world, it's very possible that during this time they helped Isshin regain his powers, or at the very least, allowed him to secretly train in Urahara's secret underground training facility.

Isshin being a family man actually supports the fact that his rate of training, and thus reawakening his powers was severely limited. Even though Ichigo comes and goes as he pleases, he still has to protect his two daughters when Ichigo isn't around.

Ichigo regained his powers so fast because he was stimulated to do so, plain and simple, like someone else mentioned.

Btw, I typed this up really fast, hope I didn't throw any huge plot holes in there.

Isshin was definitely a soul reaper who possesses captain level soul reaper ability when he fought Aizen. Plus we know he used the final getsuga tensho which means he loss his soul reaper powers,but obviously the lost of your spiritual pressure is not finite. Personally I think maybe he left the soul society because he fell in love with Ichigo's mother and I don't think soul reapers and humans can be married. Isshin was more than likely a very powerful captain probably of squad 10 or captain of the kido corps possibly but that highly unlikely. What is know he is far more than a former ordinary soul reaper.

Don't read this unless you've read the most recent manga.

Spoiler Alert! Click to show or hide

I think it's all coming together now. Isshin used to be a captain. He was a captain during the time the Quincies were being exterminated. It's possible that a bit before the extermination campaign, Isshin was on a mission and met Masaki.

When the orders were given that the extermination would take place, he made plans to escape with Masaki to the human world. I'm thinking that the head captain or someone of high power found out about these plans and tried to kill Masaki and him. At this point he could have used Final Getsuga Tenshou, effectively making him lose his powers indefinitely.

I think the above is more plausible since during the Pendulum arc, we see no signs of Isshin, so he probably escaped to the Human World before the whole Hollowfication experiments took place. (causing Urahara and Yoruichi to escape using Gigai)

Once Urahara and Yoruichi escaped to the human world, it's very possible that during this time they helped Isshin regain his powers, or at the very least, allowed him to secretly train in Urahara's secret underground training facility.

Isshin being a family man actually supports the fact that his rate of training, and thus reawakening his powers was severely limited. Even though Ichigo comes and goes as he pleases, he still has to protect his two daughters when Ichigo isn't around.

Ichigo regained his powers so fast because he was stimulated to do so, plain and simple, like someone else mentioned.

Btw, I typed this up really fast, hope I didn't throw any huge plot holes in there.

That sound like Kubo story telling. I hope it goes that way. But there has been alot of theories tho, but I wouldn't be shock if this was the real one.

Isshin was the 10th squad Captain with Misimoto his LT and Toshiro his 3rd seat, he left the soul society on a mission and ended up confronting the first coming of the espada in which he was rescued by Masaki who was infected by the same Monster, Isshin then went back to the human world to look for Masaki who he fell for, and to stop the Hollowfication infection Isshin give up his Soul reaper powers as a restrictive barrier and saved Masaki who he later married and had 3 children with before she was killed by Grandfisher, due to this death Isshin's power seal started to slowly deteriate and he re-acquired his Soul reaper powers. Isshin was a captain at a point after Uruhara's Banishment and was the actual replacement for the fist-fighting Captain who was Hollowfied back in turn back the pendulum arc. So he came after Uruhara's era but prior to Cpt Kuchiki's era